The present invention relates generally to accessing storage media, and more particularly without limitation to systems and methods accessing data from adjacent tracks on a storage medium.
Data storage systems often store data arranged in tracks. FIG. 1 shows a storage medium 1 with two exemplary tracks 20, 22 indicated as dashed lines. The tracks are segregated by servo data written within wedges 18, 19 (i.e., servo wedges). These wedges include data and supporting bit patterns 10 that are used for control and synchronization of the read/write head assembly over a desired location on storage medium 1. In particular, these wedges generally include a preamble pattern 11 followed by a servo address mark 12 (SAM). Servo address mark 12 is followed by a Gray code 13, and Gray code 12 is followed by burst information 14. It should be noted that while two tracks and two wedges are shown, hundreds of each would typically be included on a given storage medium. User data 16 is stored at bit period locations between successive servo wedges.
Data from two adjacent tracks 20, 22 often causes inter-track interference. This inter-track interference may be mitigated where the data from the adjacent track(s) is known. However, data in adjacent tracks may not be aligned resulting in an inability to accurately cancel interference from an adjacent track. Such misalignment may be evident where sync marks 17 in adjacent user data regions 16 are misaligned by an offset 99. Offset 99 may be caused by a number of factors including, but not limited to, mechanical jitter, track to track clock drift, or the like. Of note, while sync marks 17 may not be aligned, servo data 10a and servo data 10c, and servo data 10b and servo data 10d are generally aligned. Inability to calculate and compensate for offset 99 undermines the accuracy of inter-track interference mitigation. Failure to properly account for inter-track interference results in diminished accuracy of read back data.
Hence, for at least the aforementioned reasons, there exists a need in the art for advanced systems and methods for mitigating inter-track interference.